Stories of Great Scientists - Charles Gibson

The Letter Which got Galileo into Trouble

It may be of interest to some readers to see the full text of the letters referred to in Chapter IX. The first of these is a letter sent to Galileo by his old pupil, then Professor Castelli of Pisa. The occasion referred to was a dinner-party at the palace of the Grand Duke of Tuscany:

"On Thursday I dined at their Highnesses' table. The Grand Duke asked me how my lectures were attended. I entered into various minute particulars, with which he appeared much pleased. He asked whether I had a telescope. I answered that I had; and with this I gave an account of my observation of the Medicean planets the preceding night, and Madama Serenissima (the Dowager Duchess) inquired their position. And hereupon some began to say that indeed these must be realities, and not deceptions of the instrument; and their Highnesses began to question Dr. Boscaglia, the professor of physics, who answered that the existence of these planets could not be denied. I took occasion to add what I knew of your wonderful invention, and of your having fixed the periods of the revolution of the said planets. Don Antonio was at table, who showed by his countenance how much pleased he felt with what I said. At length, after many solemn ceremonies, dinner came to an end, and I took leave; but scarcely had I quitted the Palace when Madama Serenissima's porter came after me, and called me back. But before I narrate what followed, I ought to tell you that during dinner Boscaglia was talking privately to Madama for a while; and he said that, if it were conceded that the celestial novelties discovered by you were realities, then only the motion of the earth was incredible, and could not be, for the reason that Holy Scripture was manifestly contrary to it.

"To return: I entered her Highness's apartment, where were the Grand Duke, Madama the Archduchess (wife of the Grand Duke), Don Antonio, Don Paulo Giordano, and Dr. Boscaglia. Here Madama, after a few inquiries as to my condition in life, began to argue against me with the help of the Holy Scriptures; and I, after making a proper protest, began a theological exposition in such a masterly manner that you would have been delighted to hear me. Don Antonio helped me, and so encouraged me that, though the majesty of their Highnesses was enough to appal me, I behaved like a paladin. The Grand Duke and the Archduchess were on my side, and Don Paulo Giordano brought forward a passage of Scripture very opportunely in my defence. So at length Madama Serenissima was the only one who contradicted me, but it was in such a manner that I judged she only did it to draw me out. Signor Boscaglia said nothing either the one way or the other.

"All the particulars of this audience, which lasted two hours, shall be told your lordship by Signor Nicolo Arrighetti. But I ought to tell you that, as I was praising you, Don Antonio joined in, in what way you may imagine; and when I had taken leave, he offered me his services in the most princely manner, and desired me to give you an account of what had taken place, and what he had said; and said in these very words: 'Write thou to Signor Galileo that I have made thy acquaintance, and tell him what I said in her Highness's chamber.'"

Here we have a copy of Galileo's reply to his enthusiastic disciple:

"It seems to me that it was well said by Madama Serenissima, and insisted on by your reverence, that the Holy Scripture cannot err, and that the decrees therein contained are absolutely true and inviolable. But I should have in your place added that, though Scripture cannot err, its expounders and interpreters are liable to err in many ways; and one error in particular would be most grave and most frequent, if we always stopped short at the literal signification of the words. For in this wise not only many contradictions would be apparent, but grave heresies and blasphemies. For then it would be necessary to give God hands and feet and ears, and human and bodily emotions; such as anger, repentance, hatred, and sometimes forgetfulness of things past, and ignorance of the future. And in Scripture there are found many propositions, which, taking the bare sense of the words, appear contrary to the truth, but they are placed there in such wise in order to accommodate themselves to the capacity of the vulgar; so that for those few who merit to be separated from the plebeian crowd, it is necessary for wise expositors to produce the true meaning, and to explain the particular reasons for which they have been thus worded. It being laid down, therefore, that Scripture is not only capable of divers interpretations, but that in many places it requires an interpretation differing from the apparent meaning of the words, it seems to me that in mathematical disputes it must be interpretated according to the latter mode. Holy Scripture and Nature are both emanations from the Divine Word: the former dictated by the Holy Spirit; the latter, the executrix of God's commands. Holy Scripture has to be accommodated to the common understanding in many things which differ in reality from the terms used in speaking of them. But Nature, being on the contrary inexorable and immutable, and caring not one jot whether her secret reasons and modes of operation be above or below the capacity of men's understanding: it appears that, as she never transgresses her own laws, those natural effects which the experience of our senses places before our eyes, or which we infer from adequate demonstration, are in no wise to be revoked because of certain passages of Scripture, which may be turned and twisted into a thousand different meanings. For Scripture is not bound to such severe laws as those by which Nature is ruled. For this reason alone, that is, to accommodate itself to the capacities of rustic and undisciplined men, Scripture has not abstained from veiling in shadow its principal dogmas, attributing to God himself conditions differing from, and contrary to, the Divine essence. And who can assert or sustain that, in speaking incidentally of the Sun, or of the Earth, or of other created bodies, Scripture should have elected to restrain itself rigourously to the strict signification of the words used? May it not be, that, had the truth been represented to us bare and naked, its intention would have been annulled, from the vulgar being thereby rendered more contumacious and difficult of persuasion in the articles concerning their salvation? This, then, being conceded, and it being manifest that two truths cannot be contrary to each other, it becomes the office of wise expounders to labour till they find how to make these passages of Holy Word concordant with those conclusions, of which either necessary demonstration or the evidence of our senses have made us sure and certain. . . . As we cannot be certain that all the interpreters are divinely inspired, I think it would be prudent if men were forbidden to employ passages of Scripture for the purpose of sustaining what our senses or demonstrated proof may manifest to the contrary. Who can set bounds to the mind of man? Who dares assert that he already knows all that in this Universe is knowable? And on this account, beyond the articles concerning salvation and the stability of the faith, against the unchangeableness of which there is no danger of any valid and efficacious innovation being introduced, it would perhaps be best to counsel that none should be added unnecessarily; and if it be so, how much greater the disorder to add to these articles at the demand of persons who, though they may be divinely inspired, yet we see clearly that they are destitute of the intelligence necessary, not merely to disprove, but to understand, those demonstrations by which scientific conclusions are confirmed.

"I believe that the intention of Holy Writ was to persuade men of the truths necessary to salvation; such as neither Science nor other means could render credible, but only the voice of the Holy Spirit. But I do not think it necessary to believe that the same God who gave us our senses, our speech, our intellect, would have us put aside the use of these, to teach us instead such things as with their help we could find out for ourselves, particularly in the case of these sciences, of which there is not the smallest mention in the Scriptures; and, above all, in Astronomy, of which so little notice is taken that the names of all the planets are not mentioned. Surely if the intention of the Sacred writers had been to teach the people astronomy, they would not have passed the subject over so completely."

The foregoing letter is surely remarkable; it was written three hundred years ago.